End effectors are tools attached to robotic arms used to pick up articles, for example, sheets of paper or cardboard. The articles are delivered to the robot, which then has to grasp or pick up the article and move it in a pre-determined fashion for further processing. The robotic arm places the end effector in the desired location and orientation with respect to the article so that the article can be grasped via a plurality of suction cups protruding from the end effector. The cups contact the article and negative pressure is applied through the cups, thereby causing the end effector to grab the article. The robot arm can then move the article as desired.
Typically the end effector is attached to the robotic arm. The arrangement of the suction cups of the effector is usually specific to the shape or contour of the article that is desired to be grasped. For example, a planar article would have all of the suction cups arranged such that the distal end of the cups all lie in the same plane. That way, the grasping forces for each cup can be distributed equally and the article successfully grasped.
However, difficulties can arise when an end effector is configured to pick up a generally flat or planar article, but some of the flat articles presented to the end effector deviate from the expected planarity or flatness. This may result in some of the articles not being grasped correctly, if at all. Thus, there is a need to provide improved end effectors, and methods of operating the same, to address the above-noted situations where articles to be picked up deviate from the expected shape.